Optical systems used in laser printers may be characterized as having three sub-systems or assemblies, namely, a laser diode/pre-scan optical assembly, a scanning assembly, and a post scan assembly. Typically, the laser diode/pre-scan optical assembly includes a laser diode emitting a diverging laser beam, a collimation lens for collimating the beam emitted by the laser diode, and a pre-scan lens to focus the beam in a process direction prior to it striking the scanning device. During manufacturing, the distance between the laser diode and the collimation lens may be varied so as to focus the beam emitted by the laser diode relative to the collimation lens. Also during manufacturing, the position of the collimation lens assembly may be adjusted relative to the pre-scan lens. It would be desirable to have an improved apparatus for adjusting the distance between the laser diode and the collimation lens in a focus direction during manufacture. If would further be desirable to have an improved apparatus for adjusting the position of the collimation lens assembly relative to the pre-scan lens in a process direction during manufacture.